Conventionally, as this type of the stepless transmissions, a ball planetary type stepless transmission has been known that includes a transmission shaft acting as a center of rotation, plural power transmission elements capable of relatively rotating using the center axis of the transmission shaft as a center of rotation axis, and rolling bodies radially disposed to the center of rotation axis and clamped by three of the power transmission elements. In the ball planetary type stepless transmission, the rolling bodies are clamped by a first power transmission element and a second power transmission element disposed in confrontation with each other and the rolling bodies are disposed on the outer circumferential surface of a third power transmission element. In the stepless transmission, force (axial force) in the axial direction is applied to the rolling bodies from at least one of the first and second power transmission elements to thereby generate traction force (tangential force) between contact sections. Further, in the stepless transmission, a gear ratio is changed by tilting the rolling bodies. Patent Literature 1 described below discloses the ball planetary type stepless transmission. In the stepless transmission of Patent Literature 1 described below, coating is applied to the first to third power transmission elements and to the rolling bodies to increase the friction coefficient thereof so that durability is improved by the reduction of axial force resulting from the increase of the friction coefficient. Note that Patent Literature 2 described below discloses a toroidal type stepless transmission the durability of an output disk of which is improved by applying a surface treatment such as a carbonizing treatment, etc.